Current requirements for sprinkler systems containing antifreeze

NFPA further recommends

Since no listed solutions currently exist, other freeze protection design approaches must be employed for new systems.
 
For existing systems where traditional antifreeze solutions remain an option, consideration should still be given to alternatives to the use of antifreeze. It is important to remember that, while NFPA sprinkler standards allow the limited use of antifreeze in existing systems as an option to address freeze potential, they do not require the use of antifreeze in sprinkler systems. Both in designing new NFPA 13D systems and evaluating existing systems, owners and contractors are encouraged to investigate other methods of maintaining wet pipe systems in environments where freezing of pipes may be a concern. Several alternative design options exist including the use of insulation, heating areas where sprinkler piping is run, or the use of dry pipe and preaction systems in areas subject to freezing.

Where traditional antifreeze solutions are used, only the minimum necessary concentration should be considered. Where antifreeze is used in sprinkler systems, the concentration of antifreeze solution used in the system should be limited to the minimum concentration necessary for the lowest anticipated temperatures. Of course, in no event should the minimum concentration ever exceed the concentrations permitted by the applicable NFPA sprinkler standard.

If testing for antifreeze has not been conducted per the requirements of the NFPA sprinkler standards, testing should be initiated as soon as possible and be conducted by a qualified individual. NFPA recommends that homeowners with residential sprinkler systems contact a local sprinkler contractor for assistance.

This summary is current as of January 2014, and replaces the previous antifreeze alerts dated July 2010, August 2010, and April 5, 2011.

Download this summary (PDF, 509 KB).

Background
Following reports of a fire incident involving a sprinkler system that contained a high concentration antifreeze solution, research and standards development activities were begun to address concerns raised by the combustibility of antifreeze solutions in residential sprinkler systems. NFPA published several Safety Alerts providing guidance from NFPA in its role as a safety advocate. In addition, NFPA standards development activities were begun to consider and addressed the issues and these activities resulted, as more information and research became available, in successive Tentative Interim Amendments (TIAs) to NFPA sprinkler standards. What follows is a brief summary of the current antifreeze requirements in NFPA sprinkler standards.  This summary is not intended to provide all of the details or all of the provisions; the current applicable NFPA sprinkler standards, should be directly consulted for a complete and accurate understanding of the requirements related to the use of antifreeze.

Current requirements for sprinkler systems containing antifreeze – a summary
The current provisions in NFPA standards relating to the use of antifreeze in sprinkler systems concerning are contained in the following standards: 

  • NFPA 13, Standard for the Installation of Sprinkler Systems (2013 edition),
  • NFPA 13R, Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies (2013 edition)
  • NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes (2013 edition),
  •  NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems (2014 edition).

New Sprinkler Systems (i.e., installed after September 30, 2012) Containing Antifreeze – NFPA 13, NFPA 13D and NFPA 13R Sprinkler Systems
With limited exceptions, all new antifreeze systems (systems installed after September 30, 2012) are required to use listed antifreeze solutions. The listing of the antifreeze solution must indicate that the solution will not ignite when discharged from a sprinkler. The exceptions to the requirement for listed antifreeze solutions are as follows:

  • Factory premixed antifreeze solutions of propylene glycol in excess of 40% by volume are permitted in ESFR (Early Suppression Fast Response) systems where the sprinklers are listed for such use in a specific application. The listing will indicate the maximum percentage of propylene glycol that can be used with the specific sprinkler.
  • Limited use of factory premixed antifreeze solutions of propylene glycol up to 38%and glycerin up to 48%are permitted in “specific areas” of new NFPA 13D installations where approved by the authority having jurisdiction (AHJ).
  • The designer must provide documentation to the AHJ substantiating the use of traditional antifreeze solutions.
  • New systems, once installed, must be annually tested in the manner required for existing systems, summarized below.

Existing Sprinkler Systems (i.e., installed before September 30, 2012) Containing Antifreeze Existing NFPA 13D Sprinkler Systems

  • Existing NFPA13D systems (systems installed before September 30, 2012) must be tested annually by a qualified individual. NFPA 13D provides two alternative test procedures. In the first alternative, the system is drained and two solution samples are taken, one near the beginning and one near the end of the draining process. In the second alternative, the system is not drained and two solution samples are taken, one at the highest practical elevation and one at the lowest practical elevation of the system.
  • The two samples collected using either alternative procedure are then tested to verify that the specific gravity of both samples is similar. If the specific gravity of both samples is similar and if the system is found to contain factory premixed antifreeze solutions of either glycerin at a maximum concentration of 50% by volume or propylene glycol at a maximum concentration of 40% by volume ,then the existing solution is allowed to remain in service. If these conditions are not met, the existing solution must be replaced with a premixed antifreeze solution of either glycerin at a maximum concentration of 50% by volume or propylene glycol at a maximum concentration of 40% by volume (or other solutions listed specifically for use in fire protection systems).
  • The concentration of antifreeze solutions shall be limited to the minimum necessary for the anticipated minimum temperature.
  • Following the annual test, a tag must be attached to the riser indicating the date of the last test, the type and concentration of antifreeze solution, the date the antifreeze was replaced (if applicable), the name and license number of the contractor that tested and/or replaced the antifreeze solution, a statement indicating if the entire system was drained and replaced with antifreeze and a notice to test the concentration of the solution at yearly intervals per NFPA 13D.

Existing NFPA 13 and NFPA 13R Sprinkler Systems
The testing and maintenance provisions for NFPA 13 and 13R antifreeze systems are governed by NFPA 25. NFPA 25 provides that, by September 2022, existing systems (systems installed after September 30, 2012), like new systems, will be required to use only listed antifreeze solutions.  Until then, traditional antifreeze solutions may continue to be used where certain conditions, confirmed by annual testing, have been met, summarized as follows. 

Until a listed non-combustible solution is introduced into the system, antifreeze solutions in existing systems must be tested annually, prior to the onset of freezing weather.

  • If it is determined, based on records, tests or other reliable information that the solution found in the system is no longer permitted or if the type of anti-freeze cannot be reliably determined, the system must be drained and replaced with an acceptable factory premixed solution.
  • If the initial review indicates that the solution type is acceptable, test samples must be taken at the top and bottom of each system (in some cases an additional sample must be taken).
  • If all the test samples indicate a concentration of glycerin not greater than 38% by volume or propylene glycol not greater than 30% by volume, then the solution is permitted and may remain in the system.
  • Where the test samples indicate that the solution is between 38% and 50% glycerine or 30% and 40% propylene glycol, the solution may remain in the system pending the approval of a deterministic risk assessment (see NFPA 25: 5.3.4.2.1(3)).
  • If any of the samples indicate a concentration in excess of 50% glycerin or 40% propylene glycol, the system must be emptied and refilled with an acceptable solution or an alternate method of freeze protection must be employed. An acceptable solution would be a solution that contains less than 38% glycerine or 30% propylene glycol, or a solution that has been approved by the AHJ based on a deterministic risk assessment.
  • All traditional antifreeze solutions must be replaced by listed antifreeze solutions, or alternative freeze protection methods, by September 2022.

NOTE:  At this time, listed antifreeze solutions do not yet appear to be available. Until listed antifreeze solutions become available, many systems will not be able to utilize antifreeze and, as discussed in the sidebar, must look to other freeze protection design approaches.

For more information on antifreeze in sprinkler systems, including historical information, research, and reports please go to www.nfpa.org/antifreeze. Note that the NFPA standards described in this summary are, like all NFPA standards, revised and amended from time to time.  To be sure you have the most up-to-date versions of NFPA sprinkler standards, and to view the full text of those standards, visit the list of NFPA codes and standards and click on the appropriate standard (i.e. NFPA 13, 13D 13R 25). These “document info” pages also offer the option to sign up for an “Alert” feature to receive email notifications when new updates and other information is posted regarding the standard.

Important notice: This Summary is not a Formal Interpretation issued pursuant to NFPA Regulations. The summary has been prepared by NFPA.  And the understanding and interpretation of NFPA standards expressed herein reflects the personal opinion of NFPA staff and does not necessarily represent the official position of the NFPA or its Technical Committees. In addition, this document is neither intended, nor should it be relied upon, to provide professional consultation or services.


The following sections provide the current antifreeze solution requirements from the respective NFPA standards. To access the entire standard, click the title of the standard.

NFPA 13, Standard for the Installation of Sprinkler Systems (2013 edition)

3.4 Sprinkler System Type Definitions.
3.4.1 Antifreeze Sprinkler System. A wet pipe system using automatic sprinklers that contains a liquid solution to prevent freezing of the system, intended to discharge the solution upon sprinkler operation, followed immediately by water from a water supply.
3.4.1.1 Premixed Antifreeze Solution. A mixture of an antifreeze material with water that is prepared and factory-mixed by the manufacturer with a quality control procedure in place that ensures that the antifreeze solution remains homogeneous and that the concentration is as specified.

7.6* Antifreeze Systems.
7.6.1* General.
7.6.1.1 The use of antifreeze solutions shall be in conformity with state and local health regulations.
7.6.1.2 Antifreeze shall not be used in ESFR systems unless the ESFR sprinkler is listed for use with the antifreeze solution.
7.6.1.3 Where pendent sprinklers are utilized, the water shall be drained from the entire system after hydrostatic testing with water.
7.6.1.3.1 The requirements of 7.6.1.3 shall not apply where the system is hydrostatically tested with properly mixed antifreeze solution.
7.6.1.4 Where antifreeze systems are remote from the system riser, a placard shall be mounted on the system riser that indicates the number and location of all remote antifreeze systems supplied by that riser.
7.6.1.5 A placard shall be placed on the antifreeze system main valve that indicates the manufacture type and brand of the antifreeze solution, the concentration by volume of the antifreeze solution used, and the volume of the antifreeze solution used in the system.

7.6.2* Antifreeze Solutions.
7.6.2.1*
Except as permitted in 7.6.2.2, antifreeze solutions shall be listed for use in sprinkler systems.
7.6.2.2 Premixed antifreeze solutions of propylene glycol shall be permitted to be used with ESFR sprinklers where the ESFR sprinklers are listed for such use in a specific application.

23.1.3 Working plans shall be drawn to an indicated scale, on sheets of uniform size, with a plan of each floor, and shall show those items from the following list that pertain to the design of the system:
(42)Information about listed antifreeze solution used (type and amount).

NFPA 13R, Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies (2013 edition)

5.4.2* Piping in areas that cannot be maintained reliably above 40°F (4°C) shall be protected by use of one of the following methods:
(1)*Antifreeze system using a listed antifreeze solution in accordance with NFPA 13
(2) Dry pipe system
(3) Preaction system
(4) Listed dry pendent, dry upright, or dry sidewall sprinklers extended from pipe in heated areas
(5) Heat tracing in accordance with 6.7.2.2
5.4.3 Where antifreeze systems, dry pipe systems, and preaction systems are installed, they shall be installed in accordance with NFPA 13.

NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes (2013 edition):

3.3.6* Premixed Antifreeze Solution. A mixture of an antifreeze material with water that is prepared and factory-mixed by the manufacturer with a quality control procedure in place that ensures that the antifreeze solution remains homogeneous and that the concentration is as specified.

9.2* Antifreeze Systems.
9.2.1* Conformity with Health Regulations. The use of antifreeze solutions shall be in conformity with any state or local health regulations.
9.2.2* Antifreeze Solutions.
9.2.2.1 Except as permitted in 9.2.2.3, antifreeze solutions shall be listed for use in new sprinkler systems.
9.2.2.1.1 For existing systems, antifreeze solutions shall be limited to premixed antifreeze solutions of glycerine (chemically pure or United States Pharmacopoeia 96.5 percent) at a maximum concentration of 50 percent by volume, propylene glycol at a maximum concentration of 40 percent by volume, or other solutions listed specifically for use in fire protection systems.
9.2.2.2* Premixed solutions of glycerine (chemically pure or United States Pharmacopoeia 96.5 percent at a maximum concentration of 48 percent by volume or propylene glycol at a maximum concentration of 38 percent by volume shall be permitted to protect piping that is supplying sprinklers in a specific area of the dwelling unit, where acceptable to the authority having authority.
9.2.2.2.1* Documentation shall be presented to the AHJ to substantiate the use of the antifreeze solution.
9.2.2.3 The concentration of antifreeze solutions shall be limited to the minimum necessary for the anticipated minimum temperature.
9.2.2.4* The specific gravity of the antifreeze solution shall be checked by a hydrometer with a scale having 0.002 subdivisions.

9.2.5 Placard Information. A placard shall be placed on the antifreeze system main valve that indicates the manufacturer type and brand of antifreeze solution, the concentration of antifreeze solution used, and the volume of the antifreeze solution used in the system.

12.3.5* Antifreeze Systems.
12.3.5.1 Annual Antifreeze Solution Test and Replacement
Procedure.
12.3.5.1.1 Samples of antifreeze solution shall be collected by qualified individuals in accordance with 12.3.5.1.1.2 or
12.3.5.1.1.3 on an annual basis.
12.3.5.1.1.1 The system shall be drained to verify the following:
(1) The solution is in compliance with 9.2.2.1.1.
(2) The solution provides the necessary freeze protection.
12.3.5.1.1.2 Solution samples shall be taken near the beginning and near the end of the draining process.
12.3.5.1.1.3* Solution samples shall be taken at the highest practical elevation and the lowest practical elevation of the system.
12.3.5.1.2 The two samples collected in accordance with the procedures specified in 12.3.5.1.1.2 or 12.3.5.1.1.3 shall be tested to verify that the specific gravity of both samples is similar and that the solution is in compliance with 9.2.2.1.1.
12.3.5.1.2.1 The specific gravity of each solution shall be checked using a hydrometer with a suitable scale or a refractometer having a scale calibrated for the antifreeze solution.
12.3.5.1.3* If concentrations of the two samples collected in accordance with the procedures in 12.3.5.1.1.2 or 12.3.5.1.1.3 are similar and in compliance with 9.2.2.1.1, then (a) the solution drained in accordance with 12.3.5.1.1.1 can be used to refill the system, or (b) the existing undrained solution tested in accordance with 12.3.5.1.1.3 shall be permitted to continue to be used.
12.3.5.1.3.1 If the two samples are not similar and not in compliance with 9.2.2.1.1, then a solution in compliance with 9.2.2.1.1 shall be used to refill the system.
12.3.5.1.4 Tag.
12.3.5.1.4.1 A tag shall be attached to the riser indicating the date the antifreeze solution was tested.
12.3.5.1.4.2 The tag shall also indicate the type and concentration of antifreeze solution (by volume) with which the system is filled, the date the antifreeze was replaced (if applicable), the name of the contractor that tested and/or replaced the antifreeze solution, the contractor’s license number, a statement indicating if the entire system was drained and replaced with antifreeze, and a warning to test the concentration of the antifreeze solutions at yearly intervals per NFPA 13D.

NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems (2014 edition):

5.3.4* Antifreeze Systems. Annually, before the onset of freezing weather, the antifreeze solution shall be tested using the following procedure:
(1) Using installation records, maintenance records, information from the owner, chemical tests, or other reliable sources of information, the type of antifreeze in the system shall be determined.
(a) If the type of antifreeze is found to be a type that is no longer permitted, the system shall be drained completely and replaced with an acceptable solution.
(b) If the type of antifreeze cannot be reliably determined, the system shall be drained completely and replaced with an acceptable solution.
(2) If the antifreeze is not replaced in accordance with step 1, test samples shall be taken at the top of each system and at the bottom of each system.
(a) If the most remote portion of the system is not near the top or the bottom of the system, an additional sample shall be taken at the most remote portion.
(b) If the connection to the water supply piping is not near the top or the bottom of the system, an additional sample shall be taken at the connection to the water supply.
(3) The specific gravity of each solution shall be checked using a hydrometer with a suitable scale or a refractometer having a scale calibrated for the antifreeze solution.
(4) If any of the samples exhibits a concentration in excess of what is permitted by NFPA25, the system shall be emptied and refilled with a new acceptable solution. If a concentration greater than what is currently permitted by
NFPA 25 was necessary to keep the fluid from freezing, alternate methods of preventing the pipe from freezing shall be employed.
(5) If any of the samples exhibits a concentration lower than what is necessary to keep the fluid from freezing, the system shall be emptied and refilled with a new acceptable solution.
5.3.4.1 The use of antifreeze solutions shall be in conformity with state and local health regulations.
5.3.4.1.1* Listed CPVC sprinkler pipe and fittings shall be protected from freezing with glycerine only.
5.3.4.1.1.1 The use of diethylene, ethylene, or propylene glycols shall be specifically prohibited.
5.3.4.2 Except as permitted by 5.3.4.2.1 and 5.3.4.2.2, all antifreeze systems shall utilize listed antifreeze solutions.
5.3.4.2.1* For systems installed prior to September 30, 2012, listed antifreeze solutions shall not be required until September 30, 2022, where all of the following conditions are met:
(1)*The concentration of the antifreeze solution shall be limited to 50 percent glycerine by volume or 40 percent propylene glycol by volume.
(2) Newly introduced solutions shall be factory premixed antifreeze solutions (chemically pure or United States Pharmacopeia
96.5 percent).
(3)*Antifreeze systems with concentrations in excess of 30 percent propylene glycol and 38 percent glycerine shall be permitted based upon an approved deterministic risk assessment prepared by a qualified person approved by the authority having jurisdiction.
5.3.4.2.2 Premixed antifreeze solutions of propylene glycol exceeding 30 percent concentration by volume shall be permitted for use with ESFR sprinklers where the ESFR sprinklers are listed for such use in a specific application.
5.3.4.3 The antifreeze solution shall be tested at its most remote portion and where it interfaces with the wet pipe system.
5.3.4.4 When antifreeze systems have a capacity larger than 150 gal (568 L), tests at one additional point for every 100 gal (379 L) shall be made.
5.3.4.4.1 If the results indicate an incorrect freeze point at any point in the system, the system shall be drained and refilled with new premixed antifreeze.
5.3.4.4.2 For premixed solutions, the manufacturer’s instructions shall be permitted to be used with regard to the number of test points and refill procedure.

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